"Louis van Gaal is one of the best managers in the world, and I am lucky to be working with him," he said.

"I want to learn a lot of things and I cannot wait to play with Van Gaal, my new team-mates and for Manchester United."

Herrera said he was relishing the challenges that would be posed by the Premier League, adding: "I know the Premier League and really like it. I think I will grow up in the Premier League. It is one of the best leagues in the world."